Exposure is not how dark or how light an image looks!

A lot of words and only one reference which does not even apply to my favorite camera.

Those members such as myself that are technically interested in this discussion would benefit greatly from credible references provided to support statements made

There have been sensors with nonlinear response. I don't know of any modern sensors that don't have linear response to counted incident photons throughout most of their range. I don't think we'd want sensor with nonlinear response. A lot of the processing of raw files depends on linearity.

I have no idea what you mean by "linear light" in the above. We're not talking about polarization, I'm pretty sure.

You should not have snipped Jack's sentence, it makes sense as a whole.

Here's more of what Jack said: " On the other hand, after reading that paper, I was one of the beginners who early on and for quite a while believed incorrectly that digital sensors lacked 'the compressive nonlinearity typical of human perception' and was therefore convinced that as a result the raw data would produce dark images if processed linearly. Innumerable posts at the old farm based on these misconceptions.

Then, with the help of others, some of them in this thread, I learned a bit more and realized that none of that was true"

Jack never said that digital sensors were nonlinear. In fact, he implies that they are linear and that it's not a problem.

And he's right.

Just hadn't gotten around to responding to the rest of the statement. I got off this he said–I believed-he implied–but what about merry-go-round for a bit after multiple people had given it a spin.

The statement which Jack Hogan quoted is...

His response quoted a portion of that same statement a second time.

I simply addressed that part stated as an incorrect belief before heading into the reported consequences of that belief "and was therefore convinced that" which followed. I used ... at the beginning and end ... to indicate that it was one part of a longer quote. No sleight of hand intended, just breaking into easier to digest and discuss pieces rather than attempting to eat the whole pie at once.

I'll come back to it soon. Best wishes to you.

Then you'll need to go back and read what's already been discussed over several pages for the context because I'm not inclined to go back over it all again.

Bruce's article also said clearly that "sensors were linear", and he's right. He said that human visual perception is nonlinear, and he's right.

He also showed the difference between a linear image and a gamma corrected image when viewed in the conventional gamma corrected imaging world in which we still find ourselves routinely and daily functioning all these years later. Nowhere in what Bruce wrote does he say that linear image data is a problem.

What he actually said as a caption to a linear gamma photo example is: "Linear processed raw captures look very dark. But all the data is there in the image." And when viewed by someone using a monitor with conventional settings for gamma — the general audience to which the article was addressed — that's also right. It was not an article published for a presentation to peers at a professional society conference to address unconventional applications outside of the normal consumer experience with a digital camera and off the shelf software, monitor, and printing setups; which still: automatically apply gamma correction, behind the scenes, right out of the box, as we speak.

It's easy to bring up the vast world of topics and concepts which exist outside of the article's modest intention to introduce a beginner to nonlinear gamma correction of linear raw data and to continue going in the same circles. If anyone wants to continue to read into his article what they would have written for a different audience or group of users and continue hammering the same nail — it's your right to do so.

Nothing in the history of this thread explains what "linear light" is. I don't know what "nonlinear light" would be, either. If you have a clear definition in mind, please share it.

Well, there are the nonlinear Maxwell equations, say with a Kerr (cubic) nonlinearity; lasers fall into that regime, AFAIK, but that is different notion of nonlinearity. It describes nonlinear wave propagation of strong enough signals which interact with the medium and change its optical properties. Light relevant to photography propagates linearly and its intensity adds linearly (the latter also true for “nonlinear” light).

I'm tired of going in circles, so check with Jack. Whatever he says the context is, I'll go along with it to avoid getting dizzy or falling into an endless interrogation trap.

Both you and JACS "liked" his post below...

I believe the bolding is wrong. It is about the light stimulus, not about light (linear stimulus).

You may be overthinking this a bit. This was supposed to be about communicating with beginners, so nonlinear Maxwell equations may be a little off the mark for the intended target.

You're on the right track when you suggested the intensity of light which increases and decreases in a linear fashion.

Best wishes to you.

The bolding is exactly as intended, but thanks for your concern.

Then you misunderstand what Jack was saying. It’s not the light that is linear. It’s the stimulus.

You mean the stimulus from the light?

Please feel free to interpret and apply any context or meaning to any word, phrase, or statement contained anywhere in this merry-go-round and enjoy the ride, but I've lost interest. Unfortunately, it's just one of those rides which doesn't seem to go anywhere except in whatever direction various individuals wish to drag it.

Best wishes to you.

As I've now mentioned numerous times and demonstrated with sample images, if you display a linear (gamma 1.0) image on a standard monitor configured in a conventional manner (gamma approximately 2.2); using equipment and software as setup for normal average typical everyday digital still camera use, the resulting displayed image will have its final gamma out of balance and tend to look flat and dark. But if you disagree or if that is not your experience, I beleive we can still have a friendly difference in point of view in that regard and move forward.

I have no idea what the old farm reference is about. My only photographic frame of reference is that I did hard, dirty, sweaty, manual labor as a teenager bailing hay in the summer on an old farm in order to buy my first antiquated used camera to explore photography. I literally bled for that camera.

We apparently read the article with a different perception of the context, scope, or intent of what was written and arrived at a different understanding of its meaning — that's why a picture is worth a thousand words. Language is subject to a good deal of interpretation as to its perceived meaning and it's always the other person who has misinterpreted the meaning — just ask my ex. I'm ready to move on from this subject — just ask me. I'd rather be reading one of your excellent blog posts than continue wandering thru the same weeds over and over.

This happens millions (or billions) of times every day; usually automatically, behind the scenes, at multiple stages, and in the end balances the final product gamma as it should for a variety of media and even mixed media as shown in the link. It's all good as long as we keep our balance.

Bruce wrote that article long after the ICC had done their initial work. Bruce was an early advocate for color management, so he surely understood it. Why he would assume a monitor that is not color managed with what he knew is beyond my comprehension.

I'm sure it is beyond your comprehension since color management is yet another in a deep endless well of related topics neither mentioned or discussed in his article. I'm also certain you can dive down into that deep endless well and continue bringing up critiques over other related topics, which were also never mentioned or discussed in the article; over page after page, and day after day in a forum. If that's a discussion someone wants to engage in, they're welcome to take that ride.

"Why he would assume a monitor that is not color managed" — he didn't. The assumptions are entirely yours. You're assuming the subject of end to end color managed work flows, from image to monitor, was on his mind as something he wanted to discuss in this article. There's no reason to assume he intended the scope of his article to include any number of related topics, which rest unmentioned and unaddressed in that deep endless well, in the few pages of text and illustrations of the article he wrote.

One of the reasons why communication between people is often difficult and a minefield of misunderstanding is that it isn't enough to just understand what is being discussed when someone speaks or writes, you also need to understand what they are not discussing or including in what they say. Without both, it's easy to lose the context and meaning of what someone is saying and find yourself wandering around in the weeds of other topics and dragging those into the discussion. I lose interest in being dragged into those weeds after awhile, but others may love it there. The well of related topics is deep and endless; but my interest in this particular discussion and its form has worn thin.